Effect of Ouabain on Na + and K + Excretion in the Rat. ∗

Abstract

Summary

The effect of renal artery infusion of ouabain on urinary excretion of Na⁺, K⁺ and H⁺ was investigated by clearance methods in the rat. Ouabain consistently produced a 3-fold increase in K⁺ excretion and over a 2-fold increase in urinary H⁺ concentration. The effect on Na⁺ excretion was variable. About half the animals responded with a 4-fold increase in UV^Na+ and 2-fold increment in urine flow. The remainder showed no change in Na⁺ excretion. It appears that there is a definite species difference in the response to ouabain of the rat kidney on one hand, and the chicken and dog kidney on the other. The most likely explanation of the phenomenon noted in the rat is that ouabain may have a biphasic effect whereby proximal reabsorption of Na⁺ is inhibited and distal reabsorption, including cationic exchange for K⁺ and H⁺ is stimulated.